As is known to those in the respiratory care field, HME's are humidifying filters which are frequently used in medical procedures, for example in mechanical ventilator circuits such as when intubating patients, to prevent deterioration of respiratory functions. These devices capture heat and moisture on expiration, and return it to the patient on inspiration. After a certain period of usage, the HME requires to be changed in order to maintain proper functionality of the HME. During the procedure of removing or replacing the HME, the flow of air is interrupted which allows for possible contaminants or germs to enter into the patient, as well as the loss of positive end expiratory pressure (PEEP), which is not a desired result.
Various HME units have been suggested that incorporate intricate bypass structures/valves that selectively and completely isolate the HME media from the airflow path. For example, existing bypass-type HME units employ a bypass structure that is internal or through the HME media. While viable, these and other bypass-type HME units are difficult to operate (e.g., requiring a caregiver to rotate two frictionally fitting housing units relatively to each other) and/or are relatively complex and thus expensive.
In addition, while the HME unit addresses the heat and humidity concerns associated with ventilator-provided air in the breathing circuit, other drawbacks may exist. For example, it is fairly common to introduce aerosolized medication particles into the breathing circuit (e.g., via a nebulizer or metered dose inhaler) for delivery to the patient's lungs. However, where an HME unit is present in the breathing circuit, the medication particles will not readily traverse the HME media and thus not be delivered to the patient. This invention can also be used to administer inhaled medications through the bypass tubing to avoid the HME media through the use of a commonly found adapter allowing the administration of inhaled medications.
Furthermore, the HME media can become clogged with the droplets of liquid medication, in some instances leading to an elevated resistance of the HME unit. One approach for addressing these concerns is to remove the HME unit from the breathing circuit when introducing aerosolized medication. This step is time consuming, subject to errors and can result in the loss of recruited alveoli when the circuit is depressurized alongside opening the patient circuit which puts them at risk of infection from bacteria or viruses from entering into the circuit.
In light of the above, a need exists for a standalone device having an HME media bypass feature that addresses one or more of the problems associated with conventional bypass-type HME units. In certain of such usages it is also necessary to administer medication to the patient in the form of a mist or fine spray which is inhaled by the patient.
Accordingly, it would be highly beneficial and much more efficient if the HME could be removed and the flow of air would be automatically diverted into a bypass conduit allowing for the respiratory system to continue functioning without any interruption. It would also be highly beneficial for the flow of air to be returned through the HME once the HME is re-introduced into the respiratory system without the need to operate or control any bypass valves.